Low Off-State Drain Current Poly-Si TFT with Ni-Mediated Crystallization of Ultrathin a-Si

摘要

Low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs) were fabricated with a variation of poly-Si thickness between 50 and 20 nm produced by metal-induced crystallization of amorphous silicon (a-Si). It was found that the leakage current of the poly-Si TFTs decreased from 8.3 to 0.18 pA/um at V-ds = -5 V by decreasing its thickness from 50 to 20 nm. The poly-Si TFT with 20 nm thickness exhibited a field-effect mobility of 29 cm(2)/V s and minimum off-state current of 0.18 x 10(-12) A/um at V-ds = -5 V, an on/off current ratio of 4.1 x 10(7). The on/off current ratio can be increased by decreasing the layer thickness.